US8512884B2 - Perpendicular magnetic recording medium, method for producing the same, and magnetic recording/reproducing device - Google Patents

Perpendicular magnetic recording medium, method for producing the same, and magnetic recording/reproducing device Download PDF

Info

Publication number
US8512884B2
US8512884B2 US12/675,090 US67509008A US8512884B2 US 8512884 B2 US8512884 B2 US 8512884B2 US 67509008 A US67509008 A US 67509008A US 8512884 B2 US8512884 B2 US 8512884B2
Authority
US
United States
Prior art keywords
layer
intermediate layer
magnetic recording
crystal grain
single crystal
Prior art date
Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
Expired - Fee Related, expires
Application number
US12/675,090
Other languages
English (en)
Other versions
US20110151280A1 (en
Inventor
Migaku Takahashi
Shin Saito
Gohei Kurokawa
Yuzo Sasaki
Tatsu Komatsuda
Atsushi Hashimoto
Akihiko Takeo
Tomoyuki Maeda
Current Assignee (The listed assignees may be inaccurate. Google has not performed a legal analysis and makes no representation or warranty as to the accuracy of the list.)
Tohoku University NUC
Toshiba Corp
Resonac Holdings Corp
Original Assignee
Tohoku University NUC
Showa Denko KK
Toshiba Corp
Priority date (The priority date is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the date listed.)
Filing date
Publication date
Application filed by Tohoku University NUC, Showa Denko KK, Toshiba Corp filed Critical Tohoku University NUC
Assigned to KABUSHIKI KAISHA TOSHIBA, TOHOKU UNIVERSITY, SHOWA DENKO K.K. reassignment KABUSHIKI KAISHA TOSHIBA ASSIGNMENT OF ASSIGNORS INTEREST (SEE DOCUMENT FOR DETAILS). Assignors: HASHIMOTO, ATSUSHI, KOMATSUDA, TATSU, KUROKAWA, GOHEI, MAEDA, TOMOYUKI, SASAKI, YUZO, TAKAHASHI, MIGAKU, TAKEO, AKIHIKO, SAITO, SHIN
Publication of US20110151280A1 publication Critical patent/US20110151280A1/en
Application granted granted Critical
Publication of US8512884B2 publication Critical patent/US8512884B2/en
Expired - Fee Related legal-status Critical Current
Adjusted expiration legal-status Critical

Links

Images

Classifications

    • G—PHYSICS
    • G11—INFORMATION STORAGE
    • G11B—INFORMATION STORAGE BASED ON RELATIVE MOVEMENT BETWEEN RECORD CARRIER AND TRANSDUCER
    • G11B5/00—Recording by magnetisation or demagnetisation of a record carrier; Reproducing by magnetic means; Record carriers therefor
    • G11B5/84—Processes or apparatus specially adapted for manufacturing record carriers
    • G11B5/8404—Processes or apparatus specially adapted for manufacturing record carriers manufacturing base layers
    • G—PHYSICS
    • G11—INFORMATION STORAGE
    • G11B—INFORMATION STORAGE BASED ON RELATIVE MOVEMENT BETWEEN RECORD CARRIER AND TRANSDUCER
    • G11B5/00—Recording by magnetisation or demagnetisation of a record carrier; Reproducing by magnetic means; Record carriers therefor
    • G11B5/62—Record carriers characterised by the selection of the material
    • G11B5/73—Base layers, i.e. all non-magnetic layers lying under a lowermost magnetic recording layer, e.g. including any non-magnetic layer in between a first magnetic recording layer and either an underlying substrate or a soft magnetic underlayer
    • G11B5/7368—Non-polymeric layer under the lowermost magnetic recording layer
    • G11B5/7369—Two or more non-magnetic underlayers, e.g. seed layers or barrier layers
    • G11B5/737—Physical structure of underlayer, e.g. texture
    • G—PHYSICS
    • G11—INFORMATION STORAGE
    • G11B—INFORMATION STORAGE BASED ON RELATIVE MOVEMENT BETWEEN RECORD CARRIER AND TRANSDUCER
    • G11B5/00—Recording by magnetisation or demagnetisation of a record carrier; Reproducing by magnetic means; Record carriers therefor
    • G11B5/62—Record carriers characterised by the selection of the material
    • G11B5/73—Base layers, i.e. all non-magnetic layers lying under a lowermost magnetic recording layer, e.g. including any non-magnetic layer in between a first magnetic recording layer and either an underlying substrate or a soft magnetic underlayer
    • G11B5/7368—Non-polymeric layer under the lowermost magnetic recording layer
    • G11B5/7379—Seed layer, e.g. at least one non-magnetic layer is specifically adapted as a seed or seeding layer
    • G—PHYSICS
    • G11—INFORMATION STORAGE
    • G11B—INFORMATION STORAGE BASED ON RELATIVE MOVEMENT BETWEEN RECORD CARRIER AND TRANSDUCER
    • G11B5/00—Recording by magnetisation or demagnetisation of a record carrier; Reproducing by magnetic means; Record carriers therefor
    • G11B5/84—Processes or apparatus specially adapted for manufacturing record carriers
    • G11B5/851—Coating a support with a magnetic layer by sputtering

Definitions

  • the present invention relates to a perpendicular magnetic recording medium, a method for producing the same, and a magnetic recording/reproducing device that uses the perpendicular magnetic recording medium.
  • the limit for linear recording density is determined by these types of factors.
  • a perpendicular magnetic recording medium is typically prepared by sequentially providing a seed layer, an intermediate layer, a magnetic recording layer and a protective layer on top of a non-magnetic substrate. Further, after forming the protective layer, a lubricant layer is often applied to the surface of the protective layer. Furthermore, in many cases, a magnetic film known as a soft under layer (SUL) is provided beneath the seed layer.
  • SUL soft under layer
  • the intermediate layer is formed for the purpose of further enhancing the properties of the magnetic recording layer.
  • the seed layer controls the crystal orientation of the intermediate layer and the magnetic recording layer, and is said to also have the function of controlling the shape of the magnetic crystals.
  • a Co alloy material is used for the magnetic recording layer, and the crystal structure adopts a hexagonal close-packed structure. It is important that the (002) crystal plane of the hexagonal close-packed structure is parallel to the substrate surface. In other words, it is important that the crystal c-axis ([002] axis) is aligned along the perpendicular direction with as little disorder as possible.
  • Ru has been frequently used as the intermediate layer for the perpendicular magnetic recording medium as it adopts the same hexagonal close-packed structure as conventional magnetic recording layers. Crystals of the magnetic recording layer undergo epitaxial growth on the Ru (002) crystal plane, and therefore, a perpendicular magnetic recording medium having favorable crystal orientation can be obtained (for example, see Patent Document 1).
  • improving the degree of orientation of the (002) crystal plane of the Ru intermediate layer also improves the orientation of the magnetic recording layer. Accordingly, improving the recording density of the perpendicular magnetic recording medium requires an improvement in the Ru (002) plane.
  • a thick film is required to obtain superior crystal orientation, and as a result, the non-magnetic Ru weakens the pull of the flux from the head on the soft magnetic material of the soft under layer. Accordingly, conventionally a seed layer oriented in the (111) crystal plane of a face-centered cubic structure has been inserted between the soft under layer and the Ru intermediate layer (for example, see Patent Document 2).
  • the seed layer having a face-centered cubic structure yields a high degree of crystal orientation even with a thin film of approximately 5 (nm), and a Ru layer formed on the seed layer having the face-centered cubic structure has a high degree of crystal orientation even if the layer is thinner than a Ru layer deposited directly on the soft under layer.
  • One other reported method of reducing the crystal grain size of the intermediate layer and magnetic recording layer formed on the seed layer is the type of method typically employed for magnetic recording layers, namely, a method that employs a granular structure within the intermediate layer composed of crystal grain portions of Ru or the like, and grain boundary portions of an oxide or the like that surround the crystal grain portions (for example, see non-patent document 1).
  • a method that employs a granular structure within the intermediate layer composed of crystal grain portions of Ru or the like, and grain boundary portions of an oxide or the like that surround the crystal grain portions for example, see non-patent document 1.
  • an oxide magnetic layer such as CoCrPt—SiO 2 is formed on top of the intermediate layer, then the granular structure continues from the intermediate layer through to the magnetic recording layer, which promotes a reduction in the grain size of the magnetic crystal grains and segregation of the oxide, and can be expected to yield reduced noise, resulting in improved recording and reproduction properties.
  • this conversion of the intermediate layer to a granular structure does not represent a reduction in the grain size of the seed layer. Accordingly, the number of crystal grains per unit of surface area does not change. As a result, when future increases are made in the recording density, the number of magnetic crystal grains within a single bit will decrease, causing a reduction in the signal. Furthermore, increasing the relative proportion of the oxide grain boundary portions may cause oxidation of the Co of the magnetic crystal grains, resulting in a further reduction in the signal. Improving recording and reproduction properties to cope with the increase of recording densities requires not only a simple reduction in the grain size of the magnetic crystal grains, but also an increase in the number of crystal grains, namely, an increase in the density of the magnetic crystal grains.
  • Patent Document 3 discloses a method that uses Mg or Ti that adopts a hexagonal close-packed structure as the seed layer material, and then utilizes the poor wettability between these materials and the Ru used as the intermediate layer material to enable the average grain size of the Ru of the intermediate layer to be reduced to approximately 8 (nm) while maintaining favorable crystal orientation.
  • the reduced size Ru crystals formed on the seed layer including Mg or Ti tend to readily coalesce with surrounding Ru crystals.
  • each single magnetic crystal grain tends to undergo epitaxial growth not on a single Ru crystal grain within the intermediate layer, but rather on a plurality of coalesced Ru crystal grains. Because this means that there is no effective reduction in the size of the magnetic crystal grains, the expected dramatic improvements in the recording and reproduction properties tend not to be observed.
  • Achieving further improvements in the recording and reproduction properties requires a perpendicular magnetic recording medium having excellent recording and reproduction properties, which combines a reduced crystal grain size for the magnetic crystal grains with increased density, while also maintaining or improving the perpendicular orientation properties for the magnetic recording layer.
  • a perpendicular magnetic recording medium that is able to resolve the above issues and is also able to be produced easily has been keenly sought.
  • the present invention takes the above circumstances into consideration, with an object of providing a perpendicular magnetic recording medium which, by combining a reduced crystal grain size for the magnetic crystal grains with an increased density, while retaining favorable perpendicular orientation properties for the magnetic recording layer, is capable of recording and reproducing information at a high density, as well as providing a method for producing such a perpendicular magnetic recording medium and a magnetic recording/reproducing device.
  • a perpendicular magnetic recording medium including at least a soft under layer, an orientation control layer, a magnetic recording layer and a protective layer provided on a non-magnetic substrate, wherein
  • said orientation control layer comprises three or more layers including a seed layer, a first intermediate layer and a second intermediate layer, formed in that order from a side of said substrate,
  • each single crystal grain that constitutes said second intermediate layer is epitaxially grown on a single crystal grain of said first intermediate layer
  • each single crystal grain that constitutes said magnetic recording layer is epitaxially grown on a single crystal grain of said second intermediate layer
  • crystal grains that constitute said second intermediate layer are finer than crystal grains that constitute said first intermediate layer.
  • a perpendicular magnetic recording medium according to any one of (1) to (3) above, wherein the seed layer has a hexagonal close-packed structure or a face-centered cubic structure.
  • a perpendicular magnetic recording medium according to any one of (1) to (4) above, wherein the second intermediate layer has a hexagonal close-packed structure or a face-centered cubic structure, and the crystal grains of the second intermediate layer are isolated from the surrounding crystal grains by at least one of an oxide, a nitride or a void.
  • a perpendicular magnetic recording medium according to any one of (1) to (5) above, wherein in the second intermediate layer, a granular structure is formed composed of crystal grains having a hexagonal close-packed structure or a face-centered cubic structure, and grain boundary portions formed from an oxide of at least one element selected from the group consisting of Al, B, Bi, Ca, Cr, Fe, Hf, Mg, Mo, Nb, Ru, Si, Ta, Ti, W and Zr.
  • a perpendicular magnetic recording medium according to any one of (1) to (6) above, wherein in the magnetic recording layer, a granular structure is formed composed of ferromagnetic crystal grains, and crystal grain boundary portions formed from a non-magnetic oxide.
  • a perpendicular magnetic recording medium according to any one of (1) to (7) above, wherein the soft under layer is composed of a soft magnetic film, and the soft magnetic film has an amorphous structure.
  • the seed layer has a hexagonal close-packed structure, and is composed of elemental Mg, or of an alloy material containing Mg and at least one element selected from the group consisting of Y, Ti, Zr, Hf, Cr, Mo, W, V, Nb, Ta, Al, Ru, Re and Mn.
  • a perpendicular magnetic recording medium according to any one of (1) to (8) above, wherein the seed layer has a hexagonal close-packed structure, and is composed of elemental Ti, or of an alloy material containing Ti and at least one element selected from the group consisting of Y, Mg, Zr, Hf, Cr, Mo, W, V, Nb, Ta, Al, Ru, Re and Mn.
  • a perpendicular magnetic recording medium according to any one of (1) to (8) above, wherein the seed layer has a face-centered cubic structure, and is composed of elemental Al, or of an alloy material containing Al and at least one element selected from the group consisting of Y, Mg, Ti, Zr, Hf, Cr, Mo, W, V, Nb, Ta, Ru, Re and Mn.
  • the first intermediate layer is formed from Ru, Re, or an alloy thereof, and has a hexagonal close-packed structure.
  • a perpendicular magnetic recording medium according to any one of (1) to (11) above, wherein
  • the first intermediate layer contains, as the main constituent, at least one element selected from the group of elements having a face-centered cubic structure, is formed from an alloy material of the element of this main constituent and an element selected from the group of elements having a body-centered cubic structure, and
  • the first intermediate layer contains, as the main constituent, at least one element selected from the group of elements having a face-centered cubic structure, is formed from an alloy material of the element of this main constituent and an element selected from the group of elements having a hexagonal close-packed structure, and
  • a perpendicular magnetic recording medium according to any one of (1) to (11) above in which the seed layer has a hexagonal close-packed structure or a face-centered cubic structure, wherein
  • the first intermediate layer is formed from an element selected from the group of elements having a body-centered cubic structure, or an alloy material thereof,
  • the second intermediate layer is formed from an element selected from the group of elements having a hexagonal close-packed structure, or an alloy material thereof, and
  • the second intermediate layer is formed on the first intermediate layer.
  • a method for producing a perpendicular magnetic recording medium comprising forming at least a soft under layer, an orientation control layer, a magnetic recording layer and a protective layer on a non-magnetic substrate, wherein
  • said orientation control layer is formed by using a sputtering method to deposit three or more layers including a seed layer, a first intermediate layer and a second intermediate layer, in that order from a side of said substrate,
  • a single crystal grain that constitutes said second intermediate layer is epitaxially grown on each single crystal grain of said first intermediate layer
  • a single crystal grain that constitutes said magnetic recording layer is epitaxially grown on each single crystal grain of said second intermediate layer, and
  • crystal grains that constitute said second intermediate layer are reduced in size compared with crystal grains that constitute said first intermediate layer.
  • a magnetic recording/reproducing device including a perpendicular magnetic recording medium and a magnetic head which records and reproduces information on the perpendicular magnetic recording medium, wherein the perpendicular magnetic recording medium is a perpendicular magnetic recording medium according to any one of (1) to (15) above.
  • the present invention is able to provide a perpendicular magnetic recording medium having superior high recording density properties, in which the crystal c-axis of the crystal structure of the magnetic recording layer, and particularly a hexagonal close-packed structure, is oriented with small angular dispersion relative to the substrate plane, and in which the crystal grains that constitute the magnetic recording layer exhibit a high density while having an extremely small average grain size.
  • FIG. 1 is a cross-sectional schematic view of an embodiment of a perpendicular magnetic recording medium according to the present invention.
  • FIG. 2 is an expanded schematic view of a cross-section of an embodiment of a perpendicular magnetic recording medium according to the present invention.
  • FIG. 3 is a cross-sectional schematic view of an example of a magnetic recording/reproducing device that uses a perpendicular magnetic recording medium 10 according to the above embodiment.
  • FIG. 4A is a TEM photograph of the cross-section of a perpendicular magnetic recording medium of an example 1-1-1.
  • FIG. 4B is a schematic view of the TEM photograph of FIG. 4A .
  • FIG. 1 is a cross-sectional schematic view of one example of the perpendicular magnetic recording medium according to the present invention.
  • FIG. 2 is an expanded schematic view of a cross-section of one example of the perpendicular magnetic recording medium according to the present invention.
  • a perpendicular magnetic recording medium 10 that represents one example of the present invention includes at least a soft under layer 2 , an orientation control layer 9 composed of a seed layer 3 , a first intermediate layer 4 and a second intermediate layer 5 , a magnetic recording layer 6 , and a protective layer 7 formed on a non-magnetic substrate 1 .
  • FIG. 1 is merely a drawing used for explaining the configuration of the perpendicular magnetic recording medium 10 of this embodiment of the present invention, and the size, thickness and dimensions of each of the elements illustrated in the drawing may differ from the dimensional relationship within the actual perpendicular magnetic recording medium 10 . A detailed description of each layer of the perpendicular magnetic recording medium 10 is provided below.
  • non-magnetic substrate 1 there are no particular restrictions on the non-magnetic substrate 1 in the present embodiment, and any non-magnetic substrate may be used according to need.
  • substrates containing Al as the main constituent such as Al alloy substrates such as an Al—Mg alloy substrate, and substrates formed from conventional soda glass, aluminosilicate glass, crystallized glass, amorphous glass, silicon, titanium, ceramics, sapphire, quartz, or any of a variety of resins.
  • an Al alloy substrate or a crystallized glass substrate or a glass substrate such as amorphous glass is preferred.
  • a glass substrate mirror-polished substrates and low Ra substrates in which the surface roughness (Ra) is less than 1 ( ⁇ ) are particularly desirable.
  • the substrate may be textured, provided the degree of texturing is light.
  • the substrate is usually first cleaned and dried. This also applies in the present invention, and from the viewpoint of ensuring favorable adhesion of each of the layers, it is preferable that the cleaning and drying of the substrate is preferably performed prior to the formation of the layers.
  • cleaning can include not only washing with water, but also cleaning performed using etching (reverse sputtering). There are no particular limitations on the substrate size.
  • the soft under layer 2 of the present embodiment has the function of guiding the recording magnetic field from the head, and efficiently applying the perpendicular component of the magnetic field to the magnetic recording layer 6 .
  • the soft under layer 2 may be formed from any suitable material according to need, although a so-called soft magnetic film formed from a material having soft magnetic properties, such as a FeCo-based alloy, CoZrNb-based alloy or CoTaZr-based alloy, is preferred.
  • the soft under layer 2 preferably has an amorphous (non-crystalline) structure. By employing an amorphous structure, increases in the surface roughness (Ra) can be prevented, and the head floating height can be reduced, enabling a further increase in the recording density.
  • the soft under layer 2 may be a single layer, or may have a multi-layer structure if required.
  • a structure in which an extremely thin non-magnetic film of Ru or the like is sandwiched between two layers, thereby causing anti ferromagnetic coupling (AFC) between the two soft magnetic layers may be used as the soft under layer.
  • the overall thickness of the soft under layer 2 may be selected according to need, but is preferably within a range from approximately 20 (nm) to 120 (nm), and may be determined on the basis of achieving a favorable balance between the recording and reproduction properties and the overwrite (OW) properties.
  • the orientation control layer 9 of the present embodiment is provided on the soft under layer 2 , and controls the orientation of the film (the magnetic recording layer 6 ) provided directly on the orientation control layer 9 .
  • the orientation control layer 9 is composed of a plurality of layers, and includes the seed layer 3 , the first intermediate layer 4 and the second intermediate layer 5 laminated in sequence from the side of the non-magnetic substrate 1 .
  • the combination of the first intermediate layer 4 and the second intermediate layer 5 is sometimes referred to as simply “the intermediate layer”.
  • the seed layer 3 of the present embodiment is preferably a polycrystalline structure having a hexagonal close-packed structure or a face-centered cubic structure.
  • the (002) crystal orientation plane that represents the closest packed plane of a hexagonal close-packed structure, and the (111) crystal orientation plane that represents the closest packed plane of a face-centered cubic structure are geometrically equivalent. Accordingly, by using a seed layer 3 having either a hexagonal close-packed structure or a face-centered cubic structure, the (002) crystal orientation of the Ru that is widely used for the intermediate layer and the Co alloy used for the magnetic recording layer can be improved.
  • the material for forming the seed layer 3 may be selected according to need, and examples of materials that may be used include elemental Mg, Mg alloy materials containing Mg and at least one element selected from the group consisting of Y, Ti, Zr, Hf, Cr, Mo, W, V, Nb, Ta, Al, Ru, Re and Mn, elemental Ti, Ti alloy materials containing Ti and at least one element selected from the group consisting of Y, Mg, Zr, Hf, Cr, Mo, W, V, Nb, Ta, Al, Ru, Re and Mn, elemental Al, and Al alloy materials containing Al and at least one element selected from the group consisting of Y, Mg, Ti, Zr, Hf, Cr, Mo, W, V, Nb, Ta, Ru, Re and Mn.
  • elemental Mg, Mg alloy materials, elemental Ti and Ti alloy materials have a hexagonal close-packed structure
  • elemental Al and Al alloy materials have a face-centered cubic structure.
  • the average crystal grain size of the crystal grains 3 a of the seed layer 3 may be selected as required, but is preferably not less than 10 nm.
  • the average crystal grain size is more preferably not less than 10 nm and not more than 20 nm, and still more preferably not less than 10 mn and not more than 16 nm.
  • the average crystal grain size is determined by inspecting the crystalline shape of the layer using a transmission electron microscope (TEM) or the like, measuring the diameter of those crystal grains that can be clearly distinguished, and then statistically processing the plurality of diameter values to determine an average value.
  • TEM transmission electron microscope
  • the intermediate layer of the present embodiment is composed of at least two intermediate layers, that is, the intermediate layer is composed of the first intermediate layer 4 and the second intermediate layer 5 formed in that order from the side of the non-magnetic substrate 1 .
  • the crystal orientation of the magnetic recording layer 6 laminated on the intermediate layer is determined substantially by the crystal orientation of the intermediate layer, controlling the orientation of this intermediate layer is an extremely important factor in producing the perpendicular magnetic recording medium 10 .
  • the first intermediate layer 4 of the present embodiment is formed on the seed layer 3 .
  • the material for forming the first intermediate layer 4 may be selected according to need, and examples of materials that may be used include Ru, Re, and alloys having stacking faults. Elements having a body-centered cubic structure such as Cr, Mo, W, V, Nb and Ta, and alloys of these elements, may also be used.
  • the first intermediate layer 4 may also be formed as a laminate prepared by laminating a plurality of thin films of Ru, Re and/or alloy materials thereof. It is preferable that the first intermediate layer 4 is oriented in the (002) crystal plane of a hexagonal close-packed structure.
  • the first intermediate layer 4 preferably contains, as the main constituent, at least one element selected from the group of elements having a face-centered cubic structure, is preferably formed from an alloy material of the element of this main constituent and an element selected from the group of elements having a body-centered cubic structure, and is preferably a layer that combines a crystal structure oriented in the (111) crystal plane, and stacking faults (laminate defect) composed of a mixture of a face-centered cubic structure and a body-centered cubic structure.
  • the first intermediate layer 4 preferably contains, as the main constituent, at least one element selected from the group of elements having a face-centered cubic structure, is preferably formed from an alloy material of the element of this main constituent and an element selected from the group of elements having a hexagonal close-packed structure, and is preferably a layer that combines a crystal structure oriented in the (111) crystal plane, and stacking faults (laminate defect) composed of a mixture of a face-centered cubic structure and a hexagonal close-packed structure.
  • the crystal orientation plane of the first intermediate layer preferably matches that of the seed layer 3 having a hexagonal close-packed structure or face-centered cubic structure, thereby ensuring favorable orientation properties.
  • Such intermediate layers are preferable since they enables the magnetic recording layer 6 to be formed as very fine crystal grains.
  • Preferred examples of the aforementioned group of elements having a face-centered cubic structure include Pt, Pd and Ni and the like
  • preferred examples of the group of elements having a body-centered cubic structure include Nb, Mo and Cr and the like
  • examples of the group of elements having a hexagonal close-packed structure include Re, Hf and Zr and the like.
  • a plurality of crystal grains 4 a to 4 c of the first intermediate layer 4 are preferably epitaxially grown on top of each crystal grain 3 a having an average crystal grain size of not less than 10 nm within the seed layer 3 , and in order to achieve such a configuration, the wettability of the material of the intermediate layer (the first intermediate layer 4 ) relative to the material of the seed layer 3 is preferably poor.
  • the contact angle is typically used as an indicator for evaluating wettability.
  • the “contact angle” describes a value determined by dripping the melted material of the first intermediate layer 4 onto a solid sample of the material of the seed layer 3 , and evaluating the contact angle of the drop of the material of the first intermediate layer 4 relative to the solid surface of the material of the seed layer 3 .
  • the description of the wettability as being “poor” describes a state in which the contact angle is large.
  • the Ru contact angle relative to the element which is the main constituent of the seed layer 3 is within a range from 50 to 120 degrees.
  • Using a material that exhibits poor wettability relative to the material of the seed layer 3 as the material for the first intermediate layer 4 facilitates the formation of fine crystal grains when the first intermediate layer 4 is laminated on top of the seed layer 3 .
  • the thickness of the first intermediate layer 4 may be selected according to need, but is preferably within a range from 1 to 15 nm, and more preferably from 5 to 10 nm. Provided the thickness of the first intermediate layer 4 is within the range from 1 to 15 nm, the crystal orientation of the first intermediate layer 4 can be improved, while coalescence of the crystal grains can be suppressed.
  • the formation is preferably conducted under low gas pressure conditions, and the gas pressure is preferably not more than 1 Pa.
  • the gas pressure is preferably as low as possible, and in one usage example, the gas pressure is preferably set within a range from approximately 0.1 to 0.6 Pa. provided the gas pressure during formation of the first intermediate layer 4 is not more than 1 Pa, the crystal orientation properties of the first intermediate layer 4 can be preferably improved.
  • the second intermediate layer 5 of the present embodiment is formed on the first intermediate layer 4 .
  • the average crystal grain size of the second intermediate layer 5 may be selected according to need, but is preferably within a range from 1 to 7 nm. Provided the average crystal grain size is within this range, the magnetic recording layer 6 described below, which is laminated on the second intermediate layer 5 , can be formed with a very fine crystal grain structure.
  • the second intermediate layer 5 preferably has a hexagonal close-packed structure or face-centered cubic structure, and the crystal grains of the second intermediate layer are preferably isolated from the surrounding crystal grains by an oxide, a nitride and/or a void.
  • Such a configuration is preferred, as it enables increases in the crystal grain size (crystal grain coarsening) caused by the coalescence of multiple crystal grains within the second intermediate layer to be suppressed.
  • the second intermediate layer 5 is preferably formed as a granular structure composed of crystal grains having a hexagonal close-packed structure or face-centered cubic structure, and an oxide of at least one element selected from the group consisting of Al, B, Bi, Ca, Cr, Fe, Hf, Mg, Mo, Nb, Ru, Si, Ta, Ti, W and Zr, which exists at the grain boundary portions.
  • This type of structure is preferred, as it enables the magnetic recording layer 6 formed on the second intermediate layer 5 to be formed as very fine crystal grains.
  • the first intermediate layer 4 formed directly on the seed layer 3 can be formed using an element having a body-centered cubic structure such as Cr, Mo, W, V, Nb or Ta, or an alloy material of these elements.
  • the second intermediate layer 5 is preferably formed using an element selected from the group of elements having a hexagonal close-packed structure, or an alloy material thereof.
  • the seed layer 3 having a hexagonal close-packed structure or face-centered cubic structure a slight lattice displacement occurs between the (110) crystal orientation plane of the first intermediate layer 4 having a body-centered cubic structure and the (002) crystal orientation plane of the second intermediate layer 5 having a hexagonal close-packed structure.
  • coalescence of multiple crystal grains in the intermediate layers is suppressed, enabling the magnetic recording layer 6 described below to be formed as very fine crystal grains.
  • the gas pressure during formation of the first intermediate layer 4 which represents the initial growth stage of the intermediate layer, is preferably low.
  • the crystal growth is continued with the gas pressure in a low state, then the plurality of crystal grains of the intermediate layer on the seed layer 3 are more likely to undergo coalescence during the crystal growth process.
  • the crystal grains of the magnetic recording layer 6 formed on such coalesced crystals of the intermediate layer undergo epitaxial growth as single crystals, meaning a problem arises in that the size of the crystal grains of the magnetic recording layer 6 increases to substantially the crystal grain size of the coalesced crystal grains of the intermediate layer.
  • the gas pressure during deposition of the second intermediate layer 5 is preferably not less than 1.5 Pa, more preferably not less than 3 Pa, and still more preferably not less than 5 Pa and not more than 10 Pa.
  • the gas pressure during deposition of the second intermediate layer 5 is not less than 1.5 Pa, voids are generated between the crystal grains within the intermediate layer, thereby suppressing coalescence of the crystal grains.
  • a single fine crystal grain 5 a of the second intermediate layer 5 is epitaxially grown on top of a single fine crystal grain 4 a of the first intermediate layer 4 , and a single crystal grain 6 a of the magnetic recording layer 6 is then epitaxially grown on top of a single crystal grain 5 a of the second intermediate layer 5 , meaning a combination of increased density of crystaland reduced grain size can be achieved for the magnetic recording layer 6 .
  • the magnetic recording layer 6 of the present embodiment is the layer in which a signal is actually recorded, and the axis of easy magnetization (the crystal c-axis) is oriented substantially perpendicularly to the plane of the non-magnetic substrate 1 . Accordingly, the crystal structure and magnetic properties of the magnetic recording layer 6 ultimately determine the recording and reproduction properties.
  • the material for the magnetic recording layer 6 may be selected according to need, and examples of the material include thin films of Co-based alloys such as CoCr, CoCrPt, CoCrPtB, CoCrPtB—X, CoCrPtB—X—Y, CoCrPt—O, CoCrPt—SiO 2 , CoCrPt—Cr 2 O 3 , CoCrPt—TiO 2 , CoCrPt—ZrO 2 , CoCrPt—Nb 2 O 5 , CoCrPt—Ta 2 O 5 , CoCrPt-Ai 2 O 3 , CoCrPt—B 2 O 3 , CoCrPt—WO 2 , and CoCrPt—WO 3 .
  • X represents Ru or W or the like
  • Y represents Cu or Mg or the like.
  • a granular structure is formed such that the non-magnetic oxide crystal grain boundary portions surrounds the ferromagnetic Co crystal grains. This weakens the magnetic interaction between the Co crystal grains, and can therefore reduce noise.
  • the crystal structure of the magnetic recording layer 6 is preferably a hexagonal close-packed structure, wherein the (002) crystal plane is parallel to the substrate surface, namely, wherein the crystal c-axis ([002] axis) is aligned along the perpendicular direction with as little disorder as possible.
  • the full width at half maximum of a rocking curve can be used as a method of evaluating the crystal structure.
  • the formed film on the substrate is placed inside an X-ray diffraction apparatus, and the crystal plane parallel to the substrate surface is analyzed.
  • the sample being evaluated includes films that adopt a hexagonal close-packed structure such as the intermediate layer and magnetic recording layer 6 described above, the diffraction peaks corresponding with these crystal planes are observed.
  • a perpendicular magnetic recording medium 10 that uses a Co-based alloy, because the c-axis ([0002] axis) direction of the hexagonal close-packed structure is oriented perpendicularly relative to the substrate surface, a peak that corresponds with the (002) plane is observed.
  • the substrate surface is swung relative to the optical system while the Bragg angle causing the diffraction of the (002) plane is maintained.
  • a single diffraction peak (called a rocking curve) can be drawn.
  • the full width at half maximum ⁇ 50 for the rocking curve can be used as an indicator of the quality of the crystal orientation of the perpendicular magnetic recording medium 10 .
  • the methods used for forming the soft under layer 2 , the seed layer 3 , the first intermediate layer 4 , the second intermediate layer 5 and the magnetic recording layer 6 may be selected as appropriate.
  • a DC magnetron sputtering method or RF sputtering method is used.
  • an RF bias, DC bias, pulsed DC, pulsed DC bias, O 2 gas, H 2 O gas, H 2 gas or N 2 gas may also be used.
  • the sputtering gas pressure during film formation is preferably determined so as to optimize the properties of each layer.
  • the gas pressure is typically controlled within a range from approximately 0.1 to 30 (Pa), and is adjusted in accordance with the performance of the perpendicular magnetic recording medium 10 .
  • the protective layer 7 in the present embodiment is provided to protect the perpendicular magnetic recording medium 10 from damage caused by contact between the magnetic head and the perpendicular magnetic recording medium 10 .
  • the material for the protective layer 7 may be selected according to need, although the use of a carbon film or SiO 2 film is preferred, and a carbon film is particularly desirable.
  • the method used for forming the protective film of the protective layer 7 may be selected according to need, and methods such as sputtering methods and plasma CVD methods can be used, although a plasma CVD method is particularly desirable. A magnetron plasma CVD method may also be used.
  • the thickness of the protective layer 7 is preferably within a range from 1 to 10 (nm), more preferably from 2 to 6 (nm), and still more preferably from 2 to 4 (nm).
  • FIG. 3 is a cross-sectional schematic view of an example of a magnetic recording/reproducing device that uses the above perpendicular magnetic recording medium 10 .
  • the magnetic recording/reproducing device 15 illustrated in FIG. 3 includes the perpendicular magnetic recording medium 10 having the structure illustrated in FIG. 1 , a medium drive unit 11 that rotates the perpendicular magnetic recording medium 10 , a magnetic head 12 that records or reproduces information on the perpendicular magnetic recording medium 10 , a head drive unit 13 that moves the magnetic head 12 relative to the perpendicular magnetic recording medium 10 , and a recording/reproducing signal processing system 14 .
  • the recording/reproducing signal processing system 14 can process data input from externally and transmit this data as recording signals to the magnetic head 12 , as well as processing reproduction signals from the magnetic head 12 and transmitting the resulting data externally.
  • the magnetic head 12 used in the magnetic recording/reproducing device 15 of the present invention may be selected according to need, and examples of the magnetic head include not only magnetic heads that include, as the reproducing element, a magneto resistance (MR) element that uses an anisotropic magneto resistance effect (AMR), but also magnetic heads that are ideal for high recording densities and include a GMR (giant magneto resistance) element that uses a GMR effect, or a TuMR (tunnel magneto resistance) element that uses a tunneling effect or the like.
  • MR magneto resistance
  • AMR anisotropic magneto resistance effect
  • GMR giant magneto resistance
  • TuMR tunneling effect
  • the crystal structure of the magnetic recording layer 6 is oriented with minimal angular dispersion relative to the surface of the non-magnetic substrate 1 , and the crystal grains that constitute the magnetic recording layer 6 exhibit a high density while having an extremely small average grain size, and therefore a perpendicular magnetic recording medium 10 having excellent high recording density properties can be provided.
  • HD glass substrates were prepared. These HD glass substrates were set inside a vacuum chamber, and the chamber was evacuated down to a pressure of not more than 1.0 ⁇ 10 ⁇ 5 (Pa).
  • a sputtering method was then used to deposit a soft under layer of CoTaZr having a film thickness of 50 (nm) on each substrate, with the deposition conducted under an Ar atmosphere at a gas pressure of 0.6 (Pa).
  • a seed layer of Mg, Ti or Al with a thickness of 10 (nm) was deposited on each of the soft under layers under an Ar atmosphere at a gas pressure of 0.6 (Pa), and a first intermediate layer of Ru was then deposited on each of the seed layers (examples 1-1 to 1-3).
  • a second intermediate layer of Ru, Ru-3SiO 2 , Ru-3Cr 2 O 3 , Ru-3TiO 2 , Ru-6SiO 2 , Ru-6Cr 2 O 3 or Ru-6TiO 2 (mol %) with a thickness of 15 (nm) was then deposited on the first intermediate layer of each of the three types of substrate under an Ar atmosphere at a gas pressure of 5 (Pa) (examples 1-1-1 to 1-3-7).
  • a second intermediate layer of Ru with a thickness of 15 (nm) was deposited on the first intermediate layer of each of the three types of substrate under an Ar atmosphere at a gas pressure of 0.6 (Pa) (comparative examples 1-1 to 1-3).
  • a layer of CoCrPt—SiO 2 was then deposited as the magnetic recording layer on top of each of the second intermediate layers, and then a protective layer composed of a carbon film was deposited on top of the magnetic recording layer, thus completing production of a series of perpendicular magnetic recording media.
  • a lubricant was applied to each of the perpendicular magnetic recording media (examples 1-1-1 to 1-3-7, and comparative examples 1-1 to 1-3) and the recording and reproduction properties of the perpendicular magnetic recording media were evaluated using a Read/Write Analyzer 1632 and a Spin Stand S1701MP manufactured by Guzik Technical Enterprises, USA.
  • a planar TEM image was also captured for each magnetic recording layer, second intermediate layer and seed layer, and these images were used to measure the crystal grain sizes for the Co-based alloy of the magnetic recording layer, the Ru of the second intermediate layer, and the seed layer.
  • the signal-to-noise ratio (SNR), the coercive force (Hc), the value of ⁇ 50, the average crystal grain size of the Co of the magnetic recording layer, the average crystal grain size of the Ru of the second intermediate layer, and the average crystal grain size of the seed layer were evaluated for each of the examples and comparative examples.
  • the results are listed in Table 1. Each of these parameters is an indicator frequently used for evaluating the performance of a perpendicular magnetic recording medium.
  • FIG. 4A shows a TEM photograph of a cross-section of example 1-1-1
  • FIG. 4B is a schematic representation of FIG. 4A .
  • examples 1-1-1 to 1-3-7 the reduction in the grain size of the Co of the magnetic recording layer reduced the noise and improved the SNR. Larger SNR values represent superior results. Further, although the examples exhibited lower coercive force values than the comparative examples, the crystal orientation properties were favorably maintained. Accordingly, it is thought that reducing the crystal grain size of the Co of the magnetic recording layer makes the structure more susceptible to the effects of thermal fluctuation, resulting in a reduction in the apparent coercive force.
  • Soft magnetic layers were deposited as soft under layers on a plurality of glass substrates in the same manner as example 1. Subsequently, a seed layer of Mg, Mg10Ti, Mg10Al, Mg10Cr, Mg10Ru or Mg10Mn with a thickness of 5 (nm) was deposited on each of the soft under layers under an Ar atmosphere at a gas pressure of 0.6 (Pa) (examples 2-1 to 2-6).
  • a seed layer of Ni, Ni10Cr, Ni10Mn, Pt, Pt10Cr or Pt10Mn with a thickness of 5 (nm) was deposited on each of the soft under layers under an Ar atmosphere at a gas pressure of 0.6 (Pa) (comparative examples 2-1 to 2-6).
  • a first intermediate layer of Ru with a thickness of 5 (nm) was deposited on each seed layer under an Ar atmosphere at a gas pressure of 0.6 (Pa), and a second intermediate layer of Ru-10SiO 2 with a film thickness of 15 (nm) was then deposited under an Ar atmosphere at a gas pressure of 10 (Pa).
  • a layer of CoCrPt—SiO 2 was then deposited as the magnetic recording layer on each of the second intermediate layers, and then a protective layer composed of a carbon film was deposited on the magnetic recording layer, thus completing production of a series of perpendicular magnetic recording media.
  • the crystal grain size for the seed layer was smaller for comparative examples 2-1 to 2-6 than for examples 2-1 to 2-6, the crystal grain sizes for the Ru of the second intermediate layer and the Co of the magnetic recording layer were smaller for examples 2-1 to 2-6 than for comparative examples 2-1 to 2-6.
  • Soft magnetic layers were deposited as soft under layers on a plurality of glass substrates in the same manner as example 1. Subsequently, a seed layer of Mg, Ti or Al with a thickness of 5 (nm) was deposited on each of the soft under layers under an Ar atmosphere at a gas pressure of 0.6 (Pa) (examples 3-1 to 3-3).
  • a seed layer of Ru, Pt50Cr, Pt50Re, Cr or V with a thickness of 5 (nm) was deposited on each of the soft under layers under an Ar atmosphere at a gas pressure of 0.6 (Pa) (comparative examples 3-1-1 to 3-1-5).
  • a first intermediate layer of Ru, Pt50Cr, Pt50Re, Cr or V with a thickness of 10 (nm) was deposited on each seed layer under an Ar atmosphere at a gas pressure of 0.6 (Pa), and a second intermediate layer of Ru-12TiO 2 with a film thickness of 10 (nm) was then deposited under an Ar atmosphere at a gas pressure of 10 (Pa) (examples 3-1-1 to 3-3-5, and comparative examples 3-1-1 to 3-1-5).
  • the results of Table 3 confirmed that provided the seed layer used Mg, Ti or Al having a hexagonal close-packed structure or a face-centered cubic structure, then even if an alloy material that combines a (111) crystal plane orientation and stacking faults, such as Pt—Cr or Pt—Re, or an element having a body-centered cubic structure such as Cr or V was used as the first intermediate layer, a plurality of crystal grains of the first intermediate layer were epitaxially grown on each single crystal grain of the seed layer, in a similar manner to that observed when Ru having a hexagonal close-packed structure was used as the first intermediate layer.
  • the comparative examples 3-1-1 to 3-1-5 used stacking faults material for both the seed layer and the first intermediate layer, and compared with examples 3-1-1 to 3-3-5, the grain sizes within the intermediate layer and the magnetic recording layer were large and the SNR value was inferior.
  • the present invention is able to provide a perpendicular magnetic recording medium that is capable of recording and reproducing information at a high density, as well as a method for producing such a perpendicular magnetic recording medium and a magnetic recording/reproducing device.

Landscapes

  • Engineering & Computer Science (AREA)
  • Manufacturing & Machinery (AREA)
  • Magnetic Record Carriers (AREA)
  • Manufacturing Of Magnetic Record Carriers (AREA)
US12/675,090 2007-08-31 2008-08-28 Perpendicular magnetic recording medium, method for producing the same, and magnetic recording/reproducing device Expired - Fee Related US8512884B2 (en)

Applications Claiming Priority (3)

Application Number Priority Date Filing Date Title
JP2007226648A JP5397926B2 (ja) 2007-08-31 2007-08-31 垂直磁気記録媒体、その製造方法および磁気記録再生装置
JP2007-226648 2007-08-31
PCT/JP2008/065438 WO2009028621A1 (ja) 2007-08-31 2008-08-28 垂直磁気記録媒体、その製造方法および磁気記録再生装置

Publications (2)

Publication Number Publication Date
US20110151280A1 US20110151280A1 (en) 2011-06-23
US8512884B2 true US8512884B2 (en) 2013-08-20

Family

ID=40387335

Family Applications (1)

Application Number Title Priority Date Filing Date
US12/675,090 Expired - Fee Related US8512884B2 (en) 2007-08-31 2008-08-28 Perpendicular magnetic recording medium, method for producing the same, and magnetic recording/reproducing device

Country Status (4)

Country Link
US (1) US8512884B2 (ja)
JP (1) JP5397926B2 (ja)
CN (1) CN101836255B (ja)
WO (1) WO2009028621A1 (ja)

Families Citing this family (21)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US8431258B2 (en) * 2009-03-30 2013-04-30 Wd Media (Singapore) Pte. Ltd. Perpendicular magnetic recording medium and method of manufacturing the same
JP5401147B2 (ja) * 2009-03-30 2014-01-29 ダブリュディ・メディア・シンガポール・プライベートリミテッド 垂直磁気記録媒体の製造方法
JP2011123976A (ja) * 2009-12-14 2011-06-23 Showa Denko Kk 磁気記録媒体の製造方法及び磁気記録再生装置
US8048546B2 (en) * 2009-12-16 2011-11-01 Hitachi Global Storage Technologies Netherlands B.V. Perpendicular magnetic recording disk with ordered nucleation layer and method for making the disk
US20120064375A1 (en) * 2010-09-14 2012-03-15 Hitachi Global Storage Technologies Netherlands B. V. Method for manufacturing a perpendicular magnetic data recording media having a pseudo onset layer
US8592060B2 (en) 2010-12-21 2013-11-26 HGST Netherlands B.V. Perpendicular magnetic recording media having low medium noise and systems using the same
JP6265529B2 (ja) 2013-01-23 2018-01-24 昭和電工株式会社 磁気記録媒体の製造方法、磁気記録媒体及び磁気記録再生装置
JP6144570B2 (ja) 2013-08-05 2017-06-07 昭和電工株式会社 磁気記録媒体の製造方法、磁気記録媒体及び磁気記録再生装置
US9461242B2 (en) 2013-09-13 2016-10-04 Micron Technology, Inc. Magnetic memory cells, methods of fabrication, semiconductor devices, memory systems, and electronic systems
US9608197B2 (en) 2013-09-18 2017-03-28 Micron Technology, Inc. Memory cells, methods of fabrication, and semiconductor devices
US10454024B2 (en) 2014-02-28 2019-10-22 Micron Technology, Inc. Memory cells, methods of fabrication, and memory devices
US9281466B2 (en) 2014-04-09 2016-03-08 Micron Technology, Inc. Memory cells, semiconductor structures, semiconductor devices, and methods of fabrication
US9269888B2 (en) * 2014-04-18 2016-02-23 Micron Technology, Inc. Memory cells, methods of fabrication, and semiconductor devices
US9349945B2 (en) 2014-10-16 2016-05-24 Micron Technology, Inc. Memory cells, semiconductor devices, and methods of fabrication
JP6399515B2 (ja) * 2014-11-26 2018-10-03 昭和電工株式会社 垂直磁気記録媒体及び磁気記録再生装置
US9818442B2 (en) * 2014-12-01 2017-11-14 WD Media, LLC Magnetic media having improved magnetic grain size distribution and intergranular segregation
US9768377B2 (en) 2014-12-02 2017-09-19 Micron Technology, Inc. Magnetic cell structures, and methods of fabrication
US10439131B2 (en) 2015-01-15 2019-10-08 Micron Technology, Inc. Methods of forming semiconductor devices including tunnel barrier materials
JP6451011B2 (ja) * 2015-04-13 2019-01-16 昭和電工株式会社 垂直磁気記録媒体及び磁気記録再生装置
JP6416041B2 (ja) * 2015-05-29 2018-10-31 昭和電工株式会社 垂直磁気記録媒体及び磁気記録再生装置
US20170154647A1 (en) * 2015-11-30 2017-06-01 WD Media, LLC Stacked intermediate layer for perpendicular magnetic recording media

Citations (13)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JP2001006158A (ja) 1999-06-17 2001-01-12 Toshiba Corp 磁気記録媒体
US20020048693A1 (en) * 2000-09-01 2002-04-25 Kiwamu Tanahashi Perpendicular magnetic recording media and magnetic storage apparatus using the same
JP2002197630A (ja) 2000-12-25 2002-07-12 Toshiba Corp 垂直磁気記録媒体及び磁気記録再生装置
JP2004022138A (ja) 2002-06-19 2004-01-22 Fuji Electric Holdings Co Ltd 垂直磁気記録媒体及びその製造方法
US20050142388A1 (en) 2003-12-24 2005-06-30 Hitachi Global Storage Technologies Netherlands, B.V. Perpendicular magnetic recording media and magnetic storage apparatus using the same
US20050214590A1 (en) 2004-03-25 2005-09-29 Kabushiki Kaisha Toshiba Magnetic recording medium and magnetic recording apparatus
US20050255336A1 (en) * 2004-05-13 2005-11-17 Fujitsu Limited Perpendicular magnetic recording medium, method of producing the same, and magnetic storage device
JP2005353256A (ja) 2004-05-13 2005-12-22 Fujitsu Ltd 垂直磁気記録媒体およびその製造方法、磁気記憶装置
US20060057431A1 (en) 2004-09-14 2006-03-16 Hitachi Global Storage Technologies Netherlands B.V. Perpendicular magnetic recording medium and manufacturing of the same
JP2006155865A (ja) 2004-10-29 2006-06-15 Ken Takahashi 垂直磁気記録媒体および垂直磁気記録再生装置
US20060141292A1 (en) * 2004-12-27 2006-06-29 Kabushiki Kaisha Toshiba Perpendicular magnetic recording medium and magnetic recording/reproduction apparatus
US20070026260A1 (en) 2005-07-26 2007-02-01 Hitachi Global Storage Technologies Netherlands B.V. Granular recording medium for perpendicular recording and recording apparatus
US20090052074A1 (en) * 2007-08-21 2009-02-26 Hitachi Global Storage Technologies Netherlands B.V. Perpendicular magnetic recording media and magnetic storage apparatus using the same

Patent Citations (19)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JP2001006158A (ja) 1999-06-17 2001-01-12 Toshiba Corp 磁気記録媒体
US20020048693A1 (en) * 2000-09-01 2002-04-25 Kiwamu Tanahashi Perpendicular magnetic recording media and magnetic storage apparatus using the same
JP2002197630A (ja) 2000-12-25 2002-07-12 Toshiba Corp 垂直磁気記録媒体及び磁気記録再生装置
US20020164501A1 (en) * 2000-12-25 2002-11-07 Takashi Hikosaka Perpendicular magnetic recording medium and magnetic read/write apparatus
JP2004022138A (ja) 2002-06-19 2004-01-22 Fuji Electric Holdings Co Ltd 垂直磁気記録媒体及びその製造方法
US20050142388A1 (en) 2003-12-24 2005-06-30 Hitachi Global Storage Technologies Netherlands, B.V. Perpendicular magnetic recording media and magnetic storage apparatus using the same
JP2005190517A (ja) 2003-12-24 2005-07-14 Hitachi Global Storage Technologies Netherlands Bv 垂直磁気記録媒体及び磁気記憶装置
JP2005276366A (ja) 2004-03-25 2005-10-06 Toshiba Corp 磁気記録媒体及びそれを用いた磁気記録再生装置
US20050214590A1 (en) 2004-03-25 2005-09-29 Kabushiki Kaisha Toshiba Magnetic recording medium and magnetic recording apparatus
US20050255336A1 (en) * 2004-05-13 2005-11-17 Fujitsu Limited Perpendicular magnetic recording medium, method of producing the same, and magnetic storage device
JP2005353256A (ja) 2004-05-13 2005-12-22 Fujitsu Ltd 垂直磁気記録媒体およびその製造方法、磁気記憶装置
US20060057431A1 (en) 2004-09-14 2006-03-16 Hitachi Global Storage Technologies Netherlands B.V. Perpendicular magnetic recording medium and manufacturing of the same
JP2006085742A (ja) 2004-09-14 2006-03-30 Hitachi Global Storage Technologies Netherlands Bv 垂直磁気記録媒体及びその製造方法
JP2006155865A (ja) 2004-10-29 2006-06-15 Ken Takahashi 垂直磁気記録媒体および垂直磁気記録再生装置
US20070259214A1 (en) * 2004-10-29 2007-11-08 Migaku Takahashi Perpendicular Magnetic Recording Medium and Perpendicular Magnetic Recording/Reproducing Apparatus
US20060141292A1 (en) * 2004-12-27 2006-06-29 Kabushiki Kaisha Toshiba Perpendicular magnetic recording medium and magnetic recording/reproduction apparatus
US20070026260A1 (en) 2005-07-26 2007-02-01 Hitachi Global Storage Technologies Netherlands B.V. Granular recording medium for perpendicular recording and recording apparatus
JP2007035139A (ja) 2005-07-26 2007-02-08 Hitachi Global Storage Technologies Netherlands Bv 垂直磁気記録媒体及び磁気記録再生装置
US20090052074A1 (en) * 2007-08-21 2009-02-26 Hitachi Global Storage Technologies Netherlands B.V. Perpendicular magnetic recording media and magnetic storage apparatus using the same

Non-Patent Citations (2)

* Cited by examiner, † Cited by third party
Title
Japanese Office Action issued in Japanese Application No. 2007-226648 mailed Sep. 4, 2012.
S.N. Piramanayagam, et al., "Grain size reduction in CoCrPt: SiO2 perpendicular recording media with oxide-based intermediate layers," Applied Physics Letters, 2006, pp. 162504-1-162504-3, vol. 89.

Also Published As

Publication number Publication date
CN101836255B (zh) 2011-12-07
JP2009059433A (ja) 2009-03-19
CN101836255A (zh) 2010-09-15
JP5397926B2 (ja) 2014-01-22
WO2009028621A1 (ja) 2009-03-05
US20110151280A1 (en) 2011-06-23

Similar Documents

Publication Publication Date Title
US8512884B2 (en) Perpendicular magnetic recording medium, method for producing the same, and magnetic recording/reproducing device
JP5061307B2 (ja) 磁気記録媒体および磁気記録再生装置
JP5105333B2 (ja) 磁気記録媒体、その製造方法および磁気記録再生装置
US8133601B2 (en) Magnetic recording medium and magnetic recording and reproducing apparatus
JP2011034603A (ja) 垂直磁気記録媒体
JP2009087500A (ja) 垂直磁気記録媒体および磁気記録再生装置
JP5182631B2 (ja) 垂直磁気記録媒体
JP2009059402A (ja) 垂直磁気記録媒体及びそれを用いた磁気記録再生装置
US20070275269A1 (en) Magnetic recording medium and magnetic storage unit
JP2008097685A (ja) 垂直磁気記録媒体、その製造方法、および磁気記憶装置
US20070218316A1 (en) Magnetic recording medium, method of producing same, and magnetic storage apparatus
JP5105332B2 (ja) 磁気記録媒体、その製造方法および磁気記録再生装置
JP2009032356A (ja) 垂直磁気記録媒体、その製造方法および磁気記録再生装置
JP4534711B2 (ja) 垂直磁気記録媒体
JP2006155865A (ja) 垂直磁気記録媒体および垂直磁気記録再生装置
JP4772015B2 (ja) 磁気記録媒体および磁気記録再生装置
JP2008192249A (ja) 垂直磁気記録媒体、その製造方法および磁気記録再生装置
JP4552668B2 (ja) 垂直磁気記録媒体、および、その製造方法
US20100079911A1 (en) Magnetic recording medium, process for producing same, and magnetic recording reproducing apparatus using the magnetic recording medium
US20060210836A1 (en) Magnetic recording medium and magnetic storage unit
US8012613B2 (en) Magnetic recording medium, process for producing same, and magnetic recording reproducing apparatus
JP2003203330A (ja) 磁気記録媒体
JP5345543B2 (ja) 垂直磁気記録媒体の製造方法および磁気記録再生装置
JP2009146507A (ja) 垂直磁気記録媒体及び磁気記録再生装置
US20100014191A1 (en) Perpendicular magnetic recording medium and magnetic recording/reproduction apparatus

Legal Events

Date Code Title Description
AS Assignment

Owner name: TOHOKU UNIVERSITY, JAPAN

Free format text: ASSIGNMENT OF ASSIGNORS INTEREST;ASSIGNORS:TAKAHASHI, MIGAKU;SAITO, SHIN;KUROKAWA, GOHEI;AND OTHERS;SIGNING DATES FROM 20100108 TO 20100112;REEL/FRAME:024030/0057

Owner name: KABUSHIKI KAISHA TOSHIBA, JAPAN

Free format text: ASSIGNMENT OF ASSIGNORS INTEREST;ASSIGNORS:TAKAHASHI, MIGAKU;SAITO, SHIN;KUROKAWA, GOHEI;AND OTHERS;SIGNING DATES FROM 20100108 TO 20100112;REEL/FRAME:024030/0057

Owner name: SHOWA DENKO K.K., JAPAN

Free format text: ASSIGNMENT OF ASSIGNORS INTEREST;ASSIGNORS:TAKAHASHI, MIGAKU;SAITO, SHIN;KUROKAWA, GOHEI;AND OTHERS;SIGNING DATES FROM 20100108 TO 20100112;REEL/FRAME:024030/0057

REMI Maintenance fee reminder mailed
LAPS Lapse for failure to pay maintenance fees

Free format text: PATENT EXPIRED FOR FAILURE TO PAY MAINTENANCE FEES (ORIGINAL EVENT CODE: EXP.)

STCH Information on status: patent discontinuation

Free format text: PATENT EXPIRED DUE TO NONPAYMENT OF MAINTENANCE FEES UNDER 37 CFR 1.362

FP Lapsed due to failure to pay maintenance fee

Effective date: 20170820